1 Vertical Handover for PMIPv6 KANG Joon-Suk 姜俊錫

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Vertical Handover for PMIPv6

KANG Joon-Suk

姜俊錫

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Contents

Why Vertical Handover Wireless technologies Handover between 802.11 and 802.16 Procedure

802.16 => 802.11 802.11 => 802.16

Remaining Problems Comments

3

Agenda


802.16 => 802.11 802.11 => 802.16


4

Why Vertical Handover

Cost/Capacity/Coverage….. If a laptop might be able to use both a high speed wireless

LAN and a cellular technology for Internet access. Wireless LAN connections generally provide higher speeds

benefit of utilizing the higher bandwidth and lower cost Cellular technologies generally provide more ubiquitous coverage.

better mobility support and larger coverage

The laptop user might want to use a wireless LAN connection whenever one is available, and to 'fail over' to a cellular connection when the wireless LAN is unavailable.

5

Cases of Vertical HO

Switching network to select the best network

Handover

Handover

Handover

MN MN MN

6

Cases of Vertical HO

For just seamless connection

Handover

MN

7

Agenda


802.16 => 802.11 802.11 => 802.16


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Wireless technologies Wireless LAN

IEEE 802.11 Hot Spot

50~200m 4~11Mbps

Average 2Mbps Low cost

IEEE 802.16(e) Based on wireless data communication 60km/s(max 100km/s) More than 1Mbps(60km/s) MAX 70~100Mbps Hot Zone or Global coverage

Cell coverage : 20km

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Wireless technologies 3G

3GPP UMTS

3GPP2 CDMA

3.5G HSDPA(High Speed Downlink Packet Access)

3GPP release5 Based on mobile telecommunication Voice/Data Global coverage Average 2~3Mbps MAX 14.4Mbps

4G??? 100Mbps(moving)/1Gbps(standstill)

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Wireless technologies

COST Cellular > IEEE 802.16 > IEEE 802.11

Coverage Cellular > IEEE 802.16 > IEEE 802.11

IEEE 802.16 + HSDPA + WLAN ??

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Wireless Data Communication in Japan

2nd market in the world 2G

NTT Docomo PDC

KDDI CDMA One

3G NTT Docomo

W-CDMA KDDI

CDMA 2000

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Wireless Data Communication in Japan Wireless Internet

NTT Docomo Super 3G

Download speed 100Mbps/Upload speed 50Mbps Based on HSDPA/HSUPA

KDDI Ultra 3G

Similar speed to Super 3G Base on Mobile WiMAX(IEEE 802.16e) Serving with WiFi, ADSL, FTTH

SoftBank Based on HSDPA

WilCom PHS

Emobile HSDPA

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Wireless Data Communication in Korea

Netspot WiFi KT

Wibro Based on IEEE 802.16e KT

HSDPA SKT, KTF

Wibro + HSDPA KTF + KT

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Target L2

IEEE 802.11 IEEE 802.16e HSDPA

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Agenda


802.16 => 802.11 802.11 => 802.16


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Handover between 802.11 and 802.16

802.16 BS

(RAS)

802.11 APMN

Router(MAG)

LMA: Local Mobility AnchorMAG: Mobile Access GatewayRAS: Radio Access SystemACR: Access Control Router

LMAACR(MAG)

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Handover between 802.11 and 802.16

A MN that is connected to 802.16 enters a hotspot. For cost and bandwidth performance, the MN executes a vertical handover to the 802.11 network. When leaving the cell, the MN reconnects to the 802.16 network.

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Handover between 802.11 and 802.16 - entering WLAN

802.16 BS 802.11 APMN802.16

interface802.11

interface

Normal operation

BeaconLink Detected

Normal operation

Association ResponseLink UP

Association Request

CompletingLayer 3 handoverKeep interface onor

shutdown interface???

Selecting by useror

Automatically SwitchingPreparing Layer 3 handover

Authentication Response

Authentication Request

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Process To Detect and To Register new 802.16 BS

MN BSChannel Scanning

Establish uplink and downlink data connections

DL_MAP (Downlink map)

Link DetectedDCD (Downlink Channel Descriptor)

Ranging request

Link UP

UCD (Uplink Channel Descriptor)

UL_MAP (Uplink map)

Downlink synchronization

Uplink synchronization

Ranging responseInitial ranging

Registration request

Registration responseRegistration

Normal operations (data Tx/Rx and maintain synchronization)

0.2-10s

0.005-0.110s

0.005-0.080s

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Handover between 802.11 and 802.16 - leaving WLAN

802.11 AP 802.16 BSMN802.11

interface802.16

interfaceNormal operation

Link Detected

Normal operation

Link UP

Layer 3 handover

Keep interface onor

shutdown interface???

Performed if802.16 interface was turned off

Link Going Down

Preparing Layer 3 handover

Link synchronization and registration

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Agenda


802.16 => 802.11 802.11 => 802.16


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Procedure - Scenario

802.16 BS

(RAS)

802.11 APMN

Router(MAG)

LMAACR(MAG)

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Procedure - Scenario

Handover based on Network priority Just for seamless Handover

Based on the current link status Does It become weaker?

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802.16 => 802.11

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Procedure – contd.

1. Link_Detect event occurs(WLAN)

1. MIH’s Link_Detect event

2. Beacon message

2. MN is attached to the 802.11 APnMAG can acquire policy profile.

1. Perform L2 authentication & association process

3. nMAG sends PBU to LMA(to perform BU with LMA)

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

1

2

3

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4. LMA checks BCE list to find out if this MN is already attaching.

5. Register nMAG into the BCE list as a candidate MAG

6. LMA sends VPBA to nMAG1. Set up virtual tunnel between

LMA and nMAG

2. VPBA contains the information of pMAG

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

4MN’s ID MAG’s ID Proxy CoA On HNP Lifetime ….

a pMAG pMAG’s A Y

a nMAG nMAG’s A N …

BCE list5

6

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7. LMA sends New_Network_Detected message to MN(User)

1. To ask if user want to change network.

2. This massage contains information about nMAG

8. User selects network.

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

8

MN’s ID MAG’s ID Proxy CoA On L2 type Priority ….

a pMAG pMAG’s A Y 802.16

2

a nMAG nMAG’s A N 802.11

1 …

BCE list7

7

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Procedure - If User Wants to Keep Current Network

9. User sends boycott message to LMA

10. LMA deletes the entry from BCE list

11. LMA sends boycott message to nMAG

12. L2 connection is canceled between nMAG and MN

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)



2


1 …

BCE list9

9

1011

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Procedure - If User Wants to Change Network

9. User sends Change_Network message to LMA via pMAG

10. At pMAG 1. pMAG forward it to LMA

2. pMAG sends ACK to MN

3. pMAG starts fording packets destined for MN to nMAG

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)



2


1 …

BCE list10

9

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< MN’s actions > As soon as MN receives

Ack. from pMAG, MN changes layer2 interface.

MN sends Router_Solicitation via 802.11 interface

nMAG acknowledges it by Router_Advertisement

MN performs IP address configuration

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

12

11

13

14

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IP Address Configuration

Transport

IPv6

MAC1 MAC2

MN

Transport

IPv6

MAC1 MAC2

MN

If. Is Changingbut

IP is not Changing

IP = Net Prefix + IF ID from MAC1



Simple Modification of Auto-configuration process

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< Network’s actions >

15. As soon as LMA receives Network_Change from pMAG, LMA updates BCE list.

16. LMA sends Confirm_BU to nMAG

17. LMA changes forwarding path

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

1715

16



2


1 …

BCE listMN’s ID MAG’s ID Proxy CoA On L2 type Priority ….

a pMAG pMAG’s A N 802.16 2

a nMAG nMAG’s A Y 802.11 1 …

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18. After finishing IP configuration of MN, nMAG sends Handover_Complete message to pMAG and LMA

19. Previous connection is closed

1. pMAG & LMA clears binding information of MN

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)18

18

19

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Automatic Changing- Without User’s opinion

According to the network priority ex) 802.11 >> 602.16

According to the first service contract between SP and user

The early steps are same with previous procedure 1st step ~ 6th step

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Automatic Changing - Procedure

7. LMA sends Change_Network message to pMAG

8. At pMAG 1. pMAG starts forwarding

packets destined for MN to nMAG

2. pMAG forwards it to MN

3. pMAG sends Ack. To LMA* nMAG caches the packes for MN

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

8



2


1 …

BCE list7

8

8

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< MN’s actions >

9. As soon as MN receives Change_Network from pMAG, MN changes layer2 interface.

10. MN sends Router_Solicitation via 802.11 interface

11. nMAG acknowledges it by Router_Advertisement

12. MN performs IP address configuration

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

10

9

11

12

Automatic Changing - Procedure (contd.)

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IP Address Configuration

Transport

IPv6

MAC1 MAC2

MN

Transport

IPv6

MAC1 MAC2

MN

If. Is Changingbut

IP is not Changing




Simple Modification of Auto-configuration process

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< Network’s actions >

13. As soon as LMA receives Ack. from pMAG, LMA updates BCE list.

14. LMA sends Confirm_BU to nMAG


802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

1513

14



2


1 …





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16. After finishing IP configuration of MN, nMAG sends Handover_Complete message to pMAG and LMA

* nMAG releases the packes cached

16. Previous connection is closed

1. pMAG & LMA clears binding information of MN

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)16

16

17


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802.11 => 802.16

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802.11 => 802.16

When the MN detects that the signal from AP becomes weaker Signal strength Link_Going_Down How to decide a valid

threshold MN triggers HO

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

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Procedure

1. MN detects that the signal becomes weaker

2. MN starts detecting another network* If MN finds another 802.11’s network?...

3. MN tries to establish the L2 connection with 802.16 BS

4. MN sends Prepare_Handover message to nMAG

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

1

2 3

4

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Next steps are same with the step3~step17 of ‘the automatic changing procedure’ of ‘802.16 to 802.11’ Only one difference

In this case, changing policy does not follow network priority

At step 8 When nMAG receives Change_Network message, nMAG

already knew that HO must be performed. Because of step 4

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The Biggest Problem of 802.16 network

It takes very long time to detect and to register BS P19 of this ppt

Before completing connection procedure, previous connection with WLAN will be closed.

Link Up step Latency range (s)

Downlink and uplink synchronization

0.2-10

Initial ranging 0.005-0.110

Registration 0.005-0.080

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How to Solve

If detecting procedure begins early? In spite of good signal strength Is it efficient?

Maintaining L2 connection of previous 802.16 network continuously, while MN is being attached to 802.11 network HO is performed very quickly But it causes resource waste

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Second Solution

1. MN detects that the signal becomes weaker

2. MN sends Prepare_Handover message to nMAG

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

1

2




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Second Solution

3. nMAG sends Change_Network message to LMA

4. LMA updates BCE list.


6. LMA sends Confirm to nMAG

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

1

3

4MN’s ID MAG’s ID Proxy CoA On L2 type Priority ….


2


1 …



a nMAG nMAG’s A Y 802.11 1 …6

5

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Second Solution

7. At nMAG 1. nMAG starts forwarding

packets destined for MN to pMAG

2. nMAG sends Ack. To LMA

8. nMAG sends Confirm to MN

9. MN changes layer2 interface.

10. Next steps are same with previous case…..

802.16 BS

(RAS)

802.11 AP

MN

Router(nMAG)

LMAACR

(pMAG)

1

8

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Agenda


802.16 => 802.11 802.11 => 802.16


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Remaining Problems Adjusting the link Going Down threshold to allow enough time to perform full

network entry in 802.16 would require the MN to trigger an event while the connectivity to the 802.11 AP is still good.

Some solutions to optimize the handover between 802.11 and 802.16 include: Keep the 802.16 interface on Use sleep mode Speed up the network entry by providing heterogeneous information through the

802.11 interface (Information Service) 802.16 synchronization phase plays a key role in the handover latency:

Any prior knowledge for synchronization (channel descriptor messages) is critical in speeding up the handover.

Reducing the synchronization time by increasing the frequency of the channel descriptor messages comes generally at the cost of a higher bandwidth overhead (less bandwidth available for user traffic).

Keeping the 802.16 interface turned on is beneficial at the cost of additional power consumption and reduced battery life.

The use of 802.16e mechanisms including neighbor advertisement, BS synchronization, and sleep mode may prove to be helpful.

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Remaining Problems

To apply IPv6 to 802.16 Network, additional technique is needed Convergence Sublayer (CS)

IP CS/ Ethernet CS

Keeping the 802.11 interface turned on always? To reduce battery consumption, 802.11 interface is

turned on only at the coexistence area of 802.16 and 802.16 Using extra information system

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Agenda


802.16 => 802.11 802.11 => 802.16


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1 Vertical Handover for PMIPv6 KANG Joon-Suk 姜 俊錫

1 Vertical Handover for PMIPv6 KANG Joon-Suk 姜俊錫